JUDGMENT : 1. No one appears for the respondent though served. They have sent a representation by post which we have perused. 2. The question in this case is where the classification is changed, is it open to the authorities to levy the altered classification rate with retrospective effect? The Tribunal says that it cannot be done. It has since been held by this Court in Ballarpur Industries Limited v. Assistant Collector of Customs and Central Excise [ 1995 (76) E.L.T. 499 ] that it can be done but only for a period of six months prior to the date of notice under Section 11A where there are no allegations of suppression or concealment. Following the said decision, this appeal is allowed in part.